/* roulang page: index */
:root {
      --primary: #2563eb;
      --primary-hover: #1d4ed8;
      --secondary: #7c3aed;
      --accent: #0d9488;
      --text-main: #0f172a;
      --text-muted: #475569;
      --bg-light: #f8fafc;
      --border-color: #e2e8f0;
      --shadow-soft: 0 4px 20px -2px rgba(15, 23, 42, 0.05), 0 2px 6px -1px rgba(15, 23, 42, 0.03);
      --shadow-hover: 0 12px 28px -4px rgba(37, 99, 235, 0.12), 0 4px 12px -2px rgba(15, 23, 42, 0.06);
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Segoe UI", Roboto, "Microsoft YaHei", sans-serif;
      color: var(--text-main);
      background-color: #ffffff;
      -webkit-font-smoothing: antialiased;
    }
    body {
      overflow-x: hidden;
      line-height: 1.7;
    }
    .hero-bg-overlay {
      background: linear-gradient(135deg, rgba(255, 255, 255, 0.94) 0%, rgba(241, 245, 249, 0.92) 100%), url('/assets/images/c2fec171a2cf3e31.webp') center/cover no-repeat;
    }
    .deep-solution-bg {
      background: radial-gradient(circle at 80% 20%, rgba(124, 58, 237, 0.15) 0%, transparent 40%), radial-gradient(circle at 10% 80%, rgba(13, 148, 136, 0.15) 0%, transparent 50%), #0b1120;
    }
    .sound-wave-bar {
      animation: soundWave 1.4s ease-in-out infinite alternate;
    }
    @keyframes soundWave {
      0% { height: 16%; }
      50% { height: 85%; }
      100% { height: 35%; }
    }
    .card-transition {
      transition: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .card-transition:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: #cbd5e1;
    }
    details summary::-webkit-details-marker {
      display: none;
    }
    details[open] summary svg {
      transform: rotate(180deg);
    }